Screwy touch when plugged into AC usb adapter

I just bought an OEM apple USB AC plug for my touch, just like the one included with iPhone. Anyway I just plugged it in and went to use it, but the touch isn't accurate. When I touch in one area it touches in another. When I try to delete letters on the keyboard to adds more letters (mostly z's). When I unplug from the adapter it works as normal. Has anyone heard of this happening before? Is there any solution other than buying a new ac adapter?

Thanks!

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Well I went and exchanged the adapter for another and the problem still exist. Now sometimes it even says the device does not support charging. Still no ideas?